Improvement: Add Method Support to GenericSkeleton

### What

Goal: `score::mw::com::impl::GenericSkeleton` currently only supports Event communication. Since now also Methods are available it shall be extended with `GenericProxyMethod` support.

### How

1. Introduce a `GenericSkeletonMethod`.
2. Design/Decide, how the signature of `GenericSkeletonMethod` shall look like! I guess - opposed to our existing `SkeletoMethod` template, it won't be a class template at all. The signature for `RegisterHandler` most likely will register a callback with a `void*(void*)` signature, which gets called, when a method call comes in.

Depends on: https://github.com/eclipse-score/communication/issues/76

### Estimates for realization

2 weeks

### Category

- [x] Affects Detailed Design

### Requirements / Architecture

- [x] Requirements / Architecture are not affected by this change?